Widespread hydration of the back arc and the link to variable hydration of the incoming plate in the Lesser Antilles from Rayleigh wave imaging

Harmon, Nicholas, Rychert, Catherine A., Goes, Saskia, Maunder, Benjamin, Collier, Jenny, Henstock, Timothy, Lynch, Lloyd and Rietbrock, Andreas and the VoiLA Working Group (2021) Widespread hydration of the back arc and the link to variable hydration of the incoming plate in the Lesser Antilles from Rayleigh wave imaging. Geochemistry, Geophysics, Geosystems, 22 (7). ISSN 1525-2027

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Abstract

Subduction zone dynamics are important for a better understanding of natural hazards, plate tectonics, and the evolution of the planet. Despite this, the factors dictating the location and style of volcanism are not well-known. Here we present Rayleigh Wave imaging of the Lesser Antilles subduction zone using the ocean bottom and land seismic data collected as a part of the VoiLA experiment. This region is an important global endmember that represents a slow (<19 mm/yr) convergence rate of old (80–120 Ma), Atlantic lithosphere formed at a slow spreading ridge. We image the fast slab, the fast-overriding plate and the slow mantle wedge across the entire arc. We find slow velocity anomalies (∼4.1 km/s) in the mantle wedge directly beneath the arc with local minima beneath Dominica/Martinique, Montserrat and the Grenadines. We observe that slow velocities in the wedge extend 200 km into the back arc west of Martinique. The slowest mantle wedge velocity anomaly is more muted than several global wedges, likely reflecting the lower temperatures and less partial melt predicted for the Antilles. Subducted fracture zones and plate boundaries are a potential source of hydration, since they are located near the anomalies, although not directly beneath them. To match our observations, geodynamic models with a broadly hydrated mantle wedge are required, which can be achieved via deep hydration of the slab, and fluid release further into the back arc. In addition, 3-D flow and melt migration or ponding are required to explain the shape and location of our anomalies.

Item Type: Article
Additional Information: Acknowledgements: The authors would like to thank Stephen Hicks and David Schlaphorst for the assistance with data management and processing. The authors acknowledge funding from the UK's Natural Environment Research Council (NE/K010654/1, NE/K010743/1, NE/K010611/1). Data Availability Statement: Data used in this project is available from the IRIS DMC (www.iris.edu/dmc) and we used of data from the following Networks: XZ (https://doi.org/10.7914/SN/XZ_2016), WI (https://doi.org/10.18715/antilles.WI), NA (https://doi.org/10.21944/dffa7a3f-7e3a-3b33-a436-516a01b6af3f), G (https://doi.org/10.18715/GEO-SCOPE.G), GL (no Doi), MQ (no Doi), and TR (No Doi).
Uncontrolled Keywords: caribbean plate,lesser antilles,rayleigh wave,subduction,tomography,voila,geophysics,geochemistry and petrology ,/dk/atira/pure/subjectarea/asjc/1900/1908
Faculty \ School: Faculty of Science > School of Environmental Sciences
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Depositing User: LivePure Connector
Date Deposited: 21 Apr 2022 14:30
Last Modified: 13 Nov 2022 07:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/84712
DOI: 10.1029/2021GC009707

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